JP2024521630A - Production of coated textiles using photoinitiated chemical vapor deposition. - Google Patents

Abstract

A system for producing coated textiles using photoinitiated chemical vapor deposition is presented. The system includes a process chamber and a source of ultraviolet light. The process chamber includes a transparent window, a substrate stage disposed below the transparent window, and a plurality of ports. The ports include a first inlet port and a second inlet port. The first inlet port delivers a vapor phase monomer into the process chamber, and the second inlet port delivers a vapor phase initiator into the process chamber. The process chamber is controlled to deposit the monomer and the initiator on a textile substrate. A source of ultraviolet light is positioned to introduce ultraviolet light into the process chamber through the transparent window. The ultraviolet light polymerizes the monomer and initiator to coat the substrate with a polymer.
[Selected Figure] Figure 1A

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63/181,466, filed April 29, 2021, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD This application is directed generally to the field of coated textiles, including yarns, fibers and fabrics, and more particularly to the manufacture of coated textiles using photoinitiated chemical vapor deposition.

Conventional processes for manufacturing textiles such as fibers, yarns, and fabrics are solvent-based. In these processes, raw or partially finished fibers and yarns can be colored with dyes and treated for color fastness, feel, etc. In conventional processes, the article to be processed is introduced into a vat containing processing chemicals, surfactants, emulsifiers, and lubricants in a solvent. After processing, excess chemicals are discarded, which leads to polluted rivers and groundwater. Although the environmental impact of such processes is significant, these conventional technologies are widely used because they provide high throughput production of conventional fibers and fabrics.

In addition to the environmental impact of conventional processes, these processes are also unsuitable for producing hypoallergenic textiles, as inevitably some of the surfactants, emulsifiers or lubricants remain in the final product.

Therefore, there is a need in the art for improved processes for producing textiles, such as yarns, fibers and fabrics, including processes that are solvent-free and result in allergen-free products.

Therefore, in one embodiment, a system for producing coated textiles using photoinitiated chemical vapor deposition is presented. The system includes a process chamber and a source of ultraviolet (UV) light. The process chamber includes a transparent window, a substrate stage disposed below the transparent window, and a plurality of ports. The ports include a first inlet port and a second inlet port. The first inlet port transports a vapor phase monomer into the process chamber, and the second inlet port transports a vapor phase initiator into the process chamber. The process chamber is controlled to deposit the monomer and the initiator on the textile substrate. A source of ultraviolet light is positioned to introduce ultraviolet light into the process chamber through the transparent window. The ultraviolet light photoexcites the initiator, which transfers its excited state energy to the monomer, polymerizing the monomer and coating the substrate with a polymer.

In another embodiment, a system for producing coated textiles using photoinitiated chemical vapor deposition is presented. The system includes a process chamber, a source of ultraviolet light, and a controller. The process chamber includes a transparent window, a substrate stage disposed below the transparent window, a stage chiller disposed below the substrate stage, and a plurality of ports. The ports include a first inlet port, a second inlet port, and a vacuum port, where the first inlet port transports a gas phase monomer into the process chamber and the second inlet port transports a gas phase initiator into the process chamber. There may also be additional inlet ports for up to five other gas phase comonomers. The light source is positioned to introduce ultraviolet light into the process chamber through the transparent window. The ultraviolet light photoexcites the initiator, which transfers its excited state energy to the monomer, polymerizing the monomer to coat the substrate with a polymer. The controller is configured to cause polymerization of the monomer and initiator by the ultraviolet light from the light source simultaneously with deposition of the monomer and initiator on the substrate.

The above embodiments are illustrative only. Other embodiments described herein are within the scope of the disclosed subject matter.

So that the features of the present disclosure can be understood, a detailed description may be given by referring to certain embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the drawings illustrate only certain embodiments and therefore should not be considered as limiting the scope of the present disclosure, since the scope of the disclosed subject matter encompasses other embodiments as well. The drawings are not necessarily to scale, with the emphasis generally being placed on illustrating the features of certain embodiments. In the drawings, like numerals are used to denote like parts throughout the various views.

FIG. 1A depicts one embodiment of a coating chamber according to one or more aspects described herein. 1B-1E depict one embodiment of a vapor delivery system according to one or more aspects described herein. 1B-1E depict one embodiment of a vapor delivery system according to one or more aspects described herein. 1B-1E depict one embodiment of a vapor delivery system according to one or more aspects described herein. 1B-1E depict one embodiment of a vapor delivery system according to one or more aspects described herein. 1F and 1G depict one embodiment of a vapor delivery system according to one or more aspects described herein. 1F and 1G depict one embodiment of a vapor delivery system according to one or more aspects described herein. 2A and 2B depict a prior art coating of a textile. 2A and 2B depict a prior art coating of a textile. 3A and 3B depict a textile conformal covering according to one or more aspects described herein. 3A and 3B depict a conformal coating on a textile, according to one or more aspects described herein. 4A-4D depict photoinitiated chemical vapor deposition reactions according to one or more aspects described herein. 4A-4D depict photoinitiated chemical vapor deposition reactions according to one or more aspects described herein. 4A-4D depict photoinitiated chemical vapor deposition reactions according to one or more aspects described herein. 4A-4D depict photoinitiated chemical vapor deposition reactions according to one or more aspects described herein.

Corresponding reference characters indicate corresponding parts throughout the several views. The examples described herein illustrate some embodiments, but should not be construed as limiting the scope in any manner.

This disclosure relates to a single-step, high throughput (1-100 ft/min) photoinitiated chemical vapor deposition (PI-CVD) process that produces polymer films on flat and patterned substrates including textiles and plastics. This two-component process proceeds immediately upon introduction of a chemical vapor under low vacuum pressure (0.001-10 Torr) initiated by UV-C light to form poly(acrylate), poly(styrene), and poly(vinyl ether) polymers. These coatings have enhanced mechanical robustness through interfacial grafting, abrasion resistance, and increased washing stability. Zero wastewater and very little hazardous waste is generated during manufacture. This technology may be used to coat textiles with waterproof coatings, antiviral coatings, conductive coatings, or any other coating required.

Advantageously, the techniques do not require emulsifiers or surfactants, or any solvents, and are wastewater-free. Specifically, these techniques involving conjugated polymer formation eliminate concerns regarding solvation shells, immiscibility, solvent-substrate interactions, or solubility of the growing polymer chains. Real-time control of the thickness and nanostructure of the growing film can be easily achieved by controlling the flow rates of the monomers and initiators.

Advantages of the present disclosure also include simplicity. The process does not use surfactants or emulsifiers compared to conventional processes. Additionally, no carrier gas is required. In one example, light introduction is easier to operate, fix, and design than filament heaters (which require filament wiring, harnesses, and power sources).

A number of reactor configurations (geometry) may be employed in the present technology. For example, the reactor shape may be square, circular, etc. Overall dimensions may be any size required, including objectives between 10x10x10 inches (about 25.4xabout 25.4xabout 25.4 cm) and 250x250x250 inches (about 635xabout 635xabout 635 cm).

Figure 1A illustrates one embodiment of a system including a coating process chamber 100 and a light source 150. The process chamber 100 includes a transparent window 110, a substrate stage 120 disposed below the transparent window 110, a stage chiller 130 disposed below the substrate stage 120, and a number of ports 142-146. The ports 142-146 include a first inlet port 142, a second inlet port 144, and a vacuum port 146. The first inlet port 142 delivers a vapor phase monomer into the process chamber. The second inlet port 144 delivers a vapor phase initiator into the process chamber. There may also be five or more inlet ports for delivering up to five vapor phase comonomers into the process chamber.

Light source 150 is a source of ultraviolet light (wavelength < 390 nm). As shown in FIG. 1A, light source 150 is positioned to introduce ultraviolet light into process chamber 100 through transparent window 110. After introduction of the UV light, the UV light polymerizes the monomer and initiator to coat substrate 125 with polymer. The reaction is depicted in FIGS. 4A-4D. Due to the reaction rate, throughput speeds of 1-100 ft/min have been achieved.

In addition, a controller (not shown) may be used to control the deposition of the monomer and initiator onto the substrate 125 so that their polymerization is simultaneous with the ultraviolet light from the light source 150.

In one embodiment, the stage chiller 130 is configured to maintain the substrate at a selected temperature between -50°C and 25°C. In another embodiment, the vacuum port 146 is configured to maintain a vacuum of 0.001 to 10 Torr (about 0.133 to about 1333 Pa). In a further embodiment, the first inlet port 142 and the second inlet port 144 are each configured with a flow rate of 0.1 to 10 ^cm3 /sec. In one embodiment, the first inlet port 142 is orthogonal to the second inlet port 144. Optionally, additional inlet ports, for example 2 to 8 additional inlet ports, may be positioned at angles between 0 to 360 degrees from one another.

In one embodiment, the reagents, including the monomer and initiator, are delivered via a vapor delivery system 160. The vapor delivery system 160 includes a number of pipes 166, as depicted in Figures 1B-1D. In one embodiment, the monomer, initiator, and/or other reagents enter the vapor delivery system 160 via inlets 161 and 162. In another embodiment, the pipes 166 are connected using connectors, such as an L connector 163, a T connector 164, and an X connector 165. Optionally, the inlets 161 and/or 162 may be sealed, for example, using a cap 167, as shown in Figure 1C.

FIG. 1D is a close-up view of the vapor delivery system 160, showing holes 168 in the pipes 166 through which the vapor exits into the processing chamber 100. The holes 168 are also shown in the close-up view of the vapor delivery system 160 in FIG. 1E. In a further embodiment, the vapor delivery system 160 includes a heating element 169, e.g., a resistive heating tape, wrapped around one or more of the pipes 166.

In a further embodiment, the vapor delivery system 170 includes a substrate platform including an inlet hole 171 and an outlet hole 178, as shown in FIG. 1F. FIG. 1G is a cross-sectional view of the vapor delivery system 170 showing the path from the inlet hole 171 through the channel 176 to the outlet hole 178 (FIG. 1F).

Advantageously, the system does not include or require the decomposition of peroxides to coat the textile substrate due to the novel photoinitiated polymerization process. In one embodiment, the polymer coating the textile substrate 125 includes one of a poly(acrylate), poly(styrene), or poly(vinyl ether) polymer. In another embodiment, the ultraviolet light from the light source 150 includes a wavelength of 390 nanometers or less. In another embodiment, the polymer coating the textile substrate 125 includes p-doped poly(3,4-ethylenedioxythiophene).

The following applications of this technology are within the scope of this disclosure:

Water-resistant coating – a coating that protects textiles from wetting and water absorption.

PFC-free water-resistant coating: A waterproof coating that does not contain perfluorinated (fully fluorinated) compounds.

Soil-resistant coating: A coating that protects textiles from stains caused by dust, blood, oil, and other difficult-to-protect substances.

Spatial fluid management (SFM): A coating that uses a combination of hydrophobic and hydrophilic channels to redirect fluids throughout the textile.

Antimicrobial coating: A coating that actively kills microorganisms on the surface of a substrate.

Anti-corrosion film: A coating that protects a substrate from oxidation or corrosion when exposed to salt.

2A and 2B, a limitation of the prior art is apparent in that conventional coatings create a non-compliant (flexible) shell around the substrate (FIG. 2A) that does not contribute to the flexibility required for a wearable garment. FIG. 2B shows the substrate fibers embedded within the non-compliant shell depicted in FIG. 2A.

In contrast, as shown in Figures 3A and 3B, the textile substrate 125 comprises a fabric and the coating is conformally deposited around at least some of the fibers of the fabric. Some properties of the novel coating are now described. Note the difference between Figures 3A and 3B and Figures 2A and 2B. In one embodiment, the coating comprises a polymer such as that depicted in the schematic diagram shown in Figure 3A. Figure 3B shows chemical grafting of the polymer of Figure 3A to the fiber surface. The coating shown in Figure 3B exhibits superior properties to a coating layer located on the surface in a bulky form as shown in Figures 2A and 2B.

Referring now to Figures 4A and 4B, the general structures of photoinitiators and coinitiators are shown along with the general process of polymerization directly below. Three structures are shown: poly(vinyl ether), poly(acrylate), and poly(styrene), followed by the permissible groups for R2 and R3.

In another embodiment, no coinitiator is included in the polymerization process, as shown in Figures 4C and 4D. The general structure of a photoinitiator is shown with the general process of polymerization directly below it. Three structures are shown: poly(vinyl ether), poly(acrylate), and poly(styrene), followed by acceptable groups for R2 and R3.

During the deposition process, the coating has great effectiveness, including a large amount of interfacial grafting-covalent bonding between the growing film and the substrate. In addition, there is high abrasion resistance and increased cleaning stability, due at least in part to the conformal nature of the coating.

First, because no solvent is required to form the coating, completely fluorine-free coatings for waterproof or oil-repellent applications can be obtained. The applicant has observed that coatings formed using the present technology have high contact angles. Contact angle is a metric used to quantify the repellency of a coating. For example, a test is performed in which a droplet of either oil or water is placed on a surface and the angle of the droplet relative to the surface normal is calculated by viewing the droplet from the side. The higher the value of this contact angle, the more repellent the surface is to the droplet. A high contact angle for an oil droplet indicates an oil-repellent surface, and a high contact angle for a water droplet indicates a waterproof material. Conventional techniques require the use of fluorinated or perfluorinated materials (spray, electrodeposit, melt, etc.) for oil/water-repellent surfaces. In contrast, the PFC-free formulation is a grafted hydrocarbon polymer coating that produces water repellency (water contact angle between 130°-180°), oil repellency (oil contact angle between 80°-150°), and reduces water absorption (200 times less compared to the uncoated) while maintaining the original porosity of the textile on highly textured surfaces. The coating is completely free of PFCs and is composed of a two-component monomer and initiator blend made with commercially available chemicals. The formulation has a low environmental impact, produces zero wastewater, and is solvent-free.

Next, a specific working example of one embodiment is discussed.

Step 1: Load the fabric onto the sample stage, ensuring that the fabric is in close and uniform physical contact with the stage.

Step 2: Close all valves, turn on the pump, and fully open the pump valve.

Step 3: Add 3 mL of monomer stabilized with 5 wt. % thermal polymerization inhibitor to a Swagelok stainless steel ampoule.

Step 4: Add 2.7 mL of photoinitiator and 0.3 mL of α-haloester to a Swagelok stainless steel ampoule.

Step 5: Using the adjustable wrench, screw the Swagelok ampoule into the chamber port until the ampoule will not rotate.

Step 6: Once a base pressure of less than 100 mTorr (approximately 13.3 Pa) is achieved, turn on the stage chiller and allow the stage chiller to reach less than 0°C.

Step 7: Vent the initiator ampoule by turning the needle valve dial a small 1/8 turn. Venting occurs when the pressure increases by approximately 20-30 mTorr (approximately 2.7-4.0 Pa)/tube and then returns to base pressure.

Step 8: Detect leaks, if any. If the pressure continues to rise, there is a leak somewhere in the piping. Leaks can be checked by monitoring the pressure while the vacuum valve is closed and the needle valve is open.

Step 9: After draining, wrap the piping with heat wrap. Double check the thermocouple and inlet wraps.

Step 10: Close needle valve, plug in heat tape and heat to correct temperatures: Monomer: 120°C; Initiator: 120°C.

Step 11: Start heating the initiator. Once heated, start heating the monomer. Once the monomer and initiator have reached their temperature, set a timer for 10 minutes to allow for thermal equilibrium to be reached. The stage temperature should be below 0°C.

Step 12: Close the vacuum valve.

Step 13: Deposition: Place the UV lamp box on top of the chamber and turn on the UV lamp.

Step 14: Slowly open the initiator valve to 1/8 turn first, then after 30 seconds open the monomer valve to 1/8 turn. The QCM speed should jump to at least 5 Angstroms (0.5 nm)/sec after each valve is opened.

Step 15: Set the timer for 30 minutes. After this 30 minutes, deposition is complete.

Step 16: Post-deposition: When the deposition time is reached, set the pump to 0% open, remove the heat wrap, and remove the thermocouple.

Step 17: Close the monomer and initiator valves.

Step 18: Turn off the UV lamp.

Step 19: Turn off the heat wraps and separate them from the Swagelok stainless steel vials.

Step 20: After the monomers and initiator are cooled to 30°C, measure the remaining monomers and initiator.

Step 21: Record the final pressure and film thickness. Open the blank valve to vent the chamber to atmosphere.

Further details are described in U.S. Patent Application Publication No. 2019/0230745A1 (Andrew, Zhang and Baima), entitled "Electrically-heated fiber, fabric, or textile for heated apparel," published on July 25, 2019, and U.S. Patent Application Publication No. 2019/0230745A1 (Andrew, Zhang and Baima), entitled "Polymeric capacitors for energy storage devices, method of manufacture thereof and articles comprising the The same can be found in U.S. Patent Application Publication No. 2018/0269006 A1 (Andrew and Zhang), each of which is incorporated herein in its entirety.

Claims (19)

1. A system for producing a coated textile using photoinitiated chemical vapor deposition, comprising:
A processing chamber comprising:
Transparent window,
a substrate stage disposed below the transparent window; and a treatment chamber including a plurality of ports including a first inlet port and a second inlet port, the first inlet port delivering a vapor phase monomer into the treatment chamber and the second inlet port delivering a vapor phase initiator into the treatment chamber, the treatment chamber being controlled to deposit the monomer and the initiator onto a textile substrate;
a source of ultraviolet light positioned to introduce the ultraviolet light into the processing chamber through the transparent window, the ultraviolet light polymerizing the monomer and the initiator to coat the substrate with a polymer. The system of claim 1, wherein the processing chamber further includes a stage chiller disposed below the substrate stage, the stage chiller configured to maintain the substrate at a selected temperature between -50°C and 25°C. The system of claim 1, wherein the plurality of ports further includes a vacuum port, the vacuum port configured to maintain a vacuum of 0.001 to 10 Torr (approximately 0.133 to approximately 1333 Pa). 2. The system of claim 1, wherein the first and second inlet ports are each configured with a flow rate of 0.1 to 10 cm ³ /sec. The system of claim 1, wherein the system does not involve decomposition of a peroxide to coat the textile substrate. The system of claim 1, wherein the processing chamber is controlled to cause polymerization of the monomer and the initiator by the ultraviolet light from the light source simultaneously with deposition of the monomer and the initiator on the substrate. The system of claim 1, wherein the textile substrate comprises a fabric and the coating is conformally deposited around at least some fibers of the fabric. The system of claim 1, wherein the polymer coating the textile substrate comprises one of an acrylate, a polystyrene, or a poly(vinyl) polymer. The system of claim 1, wherein the ultraviolet light from the light source includes wavelengths of 390 nanometers or less. The system of claim 1, wherein the polymer coating the textile substrate comprises p-doped poly(3,4-ethylenedioxythiophene). 1. A system for producing a coated textile using photoinitiated chemical vapor deposition, comprising:
A processing chamber comprising:
Transparent window,
A substrate stage disposed below the transparent window;
a stage chiller disposed below the substrate stage; and a process chamber including a plurality of ports including a first inlet port, a second inlet port, and a vacuum port, the first inlet port delivering a vapor phase monomer into the process chamber and the second inlet port delivering a vapor phase initiator into the process chamber;
a source of ultraviolet light positioned to introduce the ultraviolet light into the processing chamber through the transparent window, the ultraviolet light polymerizing the monomer and the initiator to coat the substrate with a polymer;
and a controller configured to cause polymerization of the monomer and the initiator by the ultraviolet light from the light source simultaneously with depositing the monomer and the initiator on the substrate. The system of claim 11, wherein the stage chiller is configured to maintain the substrate at a selected temperature between -50°C and 25°C. The system of claim 11, wherein the vacuum port is configured to maintain a vacuum of 0.001 to 10 Torr (approximately 0.133 to approximately 1333 Pa). The system of claim 11, wherein the first and second inlet ports are each configured with a flow rate of 0.1 to 10 cm ³ /sec. The system of claim 11, wherein the system does not involve decomposition of a peroxide to coat the textile substrate. The system of claim 11, wherein the textile substrate comprises a fabric and the coating is conformally deposited around at least some fibers of the fabric. The system of claim 11, wherein the polymer coating the textile substrate comprises one of an acrylate, a polystyrene, or a poly(vinyl) polymer. The system of claim 11, wherein the ultraviolet light from the light source includes wavelengths of 390 nanometers or less. The system of claim 11, wherein the polymer coating the textile substrate comprises p-doped poly(3,4-ethylenedioxythiophene).

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